Download the .zip (via any of the download links), EXTRACT THE FILES FROM THE .7z FILE, using either Winrar or 7zip or any other program you might like to use. Extract it to your desktop, open up the "The Great War Patch 4.6" folder. Next double click the Installer.exe in the folder. Keep the installer so you can uninstall TGW whenever you want to play Napoleon without mods or with another mod. Launch the mod by launching Napoleon as you would normaly. If you do need any more help after this, just ask, someone is always here to help.
Make sure to install 4.6.1 after 4.6, and simply place/replace the pack in your data folder. Otherwise your game will not run with the latest NTW patch. AND REMEMBER, you need The Great War 4.5 (the main mod) otherwise 4.6 won't do much.
If you encounter text problems (like Serbia being Kingdom of Italy) got to your data folder and delete greatwartext.pack)